Astilbe for Shady Gardens

Astilbe 

If you need color in a semi-shady spot in summer and early fall then Astilbe is a plant you will want to get to know.  Astilbe, sometimes called False Spirea, will wave its airy graceful flowers and bring those dull spots to life.  Astilbe has few disease or insect problems and is resistant to deer and other animals. 

Astilbe looks good in masses of one color or mixed with perennials such as hosta that also appreciate moisture.   Astilbe can furnish the shade at the feet of lilies and also mixes well with daylilies.  They also attract butterflies and are good for butterfly gardens that receive some shade or in naturalized woodland gardens that need a splash of color.  Astilbe makes a good cut flower and is sometimes forced in pots for winter bloom.  Astilbe flowers also dry well.

Astilbe will grow well in zones 4-6.  There are several native Asian species from which our cultivated varieties were developed.   Some varieties have dark green leaves, some have a maroon tint to the leaves and stems and some are a lighter green.  There is at least one variety that has burgundy-purple leaves.  The leaves are compound, with serrated edges, and somewhat fern like. New leaves are glossy, but this fades as the season progresses.  Some astilbe plants have good fall colors of yellow and orange also. Astilbe plants form mounding clumps, slowly increasing in size each year if they are happy. The height of the plants, including flower spikes, ranges from 10 inches to 4 foot or more high.

Astilbe has tiny flowers all packed close together in plumes. The plumes are at the top of the plant, above the foliage.   Some flower plumes are upright, thick clusters and some are narrow and gracefully arching.   Astilbe flower colors range from lavender to all shades of red, pink and white.  The flower plumes are long lasting and dry nicely for arrangements.

Growing Astilbe

Astilbe is generally purchased as a bare root or potted plant.   They are hardy and can be planted outside as soon as the soil can be worked.   If you can, work lots of compost, sphagnum peat, aged manure or other organic material into the soil before planting.  Astilbe likes partial shade or but will grow in full sun if kept moist.  It will survive in deeper shade but will not bloom as well.  They prefer loose, fertile soil but the primary key to their success is plentiful moisture.   While astilbe do grow in shade, their shallow root systems have a hard time competing with tree roots for moisture.  If lacking water astilbe will dry up and go dormant or die.   

When growth begins in the spring fertilize astilbe with a general purpose, slow release fertilizer.  Check to make sure the roots of the plant are not exposed, as the shallow roots are prone to being heaved out of the ground over winter.  If they are, gently dig under them and settle them back into the soil.   Keep astilbe watered well if the weather is dry and they should reward you with beautiful color.   By selecting different varieties you can have astilbe in bloom from late June through September.  You can deadhead them if you like or allow the plumes to dry on the plant.  After a hard frost has killed the leaves, trim off dead leaves and stems and lightly mulch with oak leaves or pine needles to help prevent astilbe from being heaved out of the ground.

Astible in lightly shaded garden.

If your plants are doing well the clumps should increase, and they will need to be divided every 3-4 years.  Dig up the plant in early spring and divide the clump into several pieces with a sharp knife.  Replant immediately and water well.   Extra plants can be potted to share with friends.

Some varieties

‘Rheinland’ is bright pink, upright and early blooming, ‘Spinall’ has airy upright plumes of bright red and reddish foliage, ‘Ostrich Plume’ has tall, pink drooping plumes, ‘White Gloria’ has thick white plumes in mid summer, ‘Bridal Veil’ has later, tall white plumes, ‘Taqueti’ hybrids are tall, in lavender pink shades for late summer, ‘Pumila’ is a short lavender spiked variety good as a groundcover.   ‘Sprite’ is shell pink with arching flower sprays, ‘Lollypop’ is bright pink with bronze foliage, ‘’Visions has short compact spikes of purple and is said to have a soft, pleasant scent, ‘Sister Theresa’ is a salmon pink that is also scented.  ‘Red Sentinel’ has fire red, compact plumes.  ‘Color Flash’ has interesting foliage in burgundy and purple with soft pink plumes.  ‘Finale’ is one of the latest to bloom with drooping, soft rose plumes.